‘He was very kind and politically engaged, and he cared about the world around us. All of that was very attractive to me,’ said Hughes about Eldridge, The New York Times reports.

‘We have a love of philosophy, politics and literature. He was one of the most intelligent and ambitious people I had ever met.’

Eldridge, 25, is a campaigner for Protect our Democracy, a group seeking political campaign finance reform, and Freedom to Marry, a group advocating same-sex marriage across the US. He is also president of investment company Hudson River Ventures.

Hughes was the online campaign manager for Barack Obama’s 2008 presidential campaign. Fast Company magazine described him as ‘the kid who made Obama president’.

This year Hughes bought highbrow American arts and politics magazine The New Republic, becoming publisher and editor-in-chief.

Forbes estimates that the couple have a joint fortune of $700 million (€550 million).

A profile in The New York Times this May called the couple ‘a significant force in political circles’ and said that they regularly host fundraisers for progressive causes in their 4,000-square-foot loft apartment in Soho, New York City.

Hughes and Eldridge were the cover stars for The Advocate magazine’s Forty under 40. In the accompanying article, Hughes said he proposed to Eldridge on New Year’s Eve in Thailand. 'For a couple of days, we were all smiles,' said Eldridge. 'Then we realized we have to plan a wedding.'